99% of HP is in third limited from Harry's POV. But most of the books start with a single chapter either in third limited from another character's perspective (e.g. Goblet of Fire, which starts from Frank Bryce's perspective) or omniscient (e.g. Deathly Hallows). JK Rowling also begins some chapters with one or two 'panning' lines about the weather or the mood of the school, which feel detached from Harry's POV, and then switches to Harry's head. But she didn't head hop in the middle of chapters. She had to create a whole bunch of plot devices to allow us to see events without Harry present without hopping from Harry's POV - e.g. the trip into Riddle's diary, the bowl of memories (can't remember its name), letters from his parents, etc.
I have a new question on this subject. Given I'm writing close third, how do I deliver exposition / details on a character's history or background, without it sounding like I've switched to a distant omniscient POV?
How do you do it in your preferred method first person, which is the opposite of distant? Does it sound like it's rocketed away into omniscient then?
Well no, because it's all done with the pronoun of 'I' I opened the door and stepped into the room. Sounds no different to me than: Four years ago I was a clean-living guy, but not now. One is action, the other is exposition, but it's still 'me' telling the story.
Four years ago he was a clean-living guy, but not now. Pretty much the same. If the thought would flit through the character's mind, it's fair game.
I understand it's pretty much just swapping the pronouns out, but to me it's a distinct omniscient voice who's talking when I do the exposition. I can't explain why that is. Maybe it's because with the action scenes I'm in the 'now' whereas with exposition I'm revealing a history which distances me from the character. Anyway, so long as I know it's not jarring I can carry on. Thanks, both.